1. Field of the Invention
The present invention relates to a method for measuring sample by enzyme electrodes, more particularly to a method for measuring a specified component in a body fluid, for example, blood, blood plasma, urine and so on by using the enzyme electrodes.
2. Description of the Prior Art
Recently enzyme electrodes have been employed for measuring a specified component in a body fluid, e.g. blood. For example, in a quantitative analysis of glucose, a glucose sensor which is formed by fixing a membrane of glucose oxidizing enzyme on the surfaces of hydrogen peroxide electrodes is employed. After a measurement voltage is applied to the electrodes of glucose sensor, buffer solution is charged in a reaction container so that the ends of glucose sensor can be immersed. An electric current between the electrodes becomes stable and then a sample is injected in the buffer solution. The quantity of glucose can be obtained by measuring the change in the electric current between electrodes from the time point of sample injection.
Since it has taken 1-5 minutes for the electric current to become stable after charging the buffer solution, it was necessary to wait for long time to commence the injection of sample and the measurement, which resulted in a greatly inefficient operation.
A method for stabilizing early electric current between enzyme electrodes has been proposed in Japanese patent laid-open publication No. 62-294954. In this method, a higher voltage than measurement voltage is applied to the enzyme electrodes and then the measurement voltage is applied thereto. According to the method, although the stable point of the current becomes a little early, it needs to wait for the current to become stable nevertheless.